我在互联网上找到了这段代码,我尝试用它来打印 PDF 文档,如果我从该代码外部打印相同的文档,打印机可以正常工作。
在这种情况下,我可以看到打印队列中的作业,它已被处理,并且函数 WritePrinter 成功返回,但没有打印任何内容。
有人可以帮我解决这个问题吗?
public class PrinterHelper
{
// Structure and API declarions:
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
public class DOCINFOA
{
[MarshalAs(UnmanagedType.LPStr)]
public string pDocName;
[MarshalAs(UnmanagedType.LPStr)]
public string pOutputFile;
[MarshalAs(UnmanagedType.LPStr)]
public string pDataType;
}
[DllImport("winspool.Drv", EntryPoint = "OpenPrinterA", SetLastError = true, CharSet = CharSet.Ansi, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool OpenPrinter([MarshalAs(UnmanagedType.LPStr)] string szPrinter, out IntPtr hPrinter, IntPtr pd);
[DllImport("winspool.Drv", EntryPoint = "ClosePrinter", SetLastError = true, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool ClosePrinter(IntPtr hPrinter);
[DllImport("winspool.Drv", EntryPoint = "StartDocPrinterA", SetLastError = true, CharSet = CharSet.Ansi, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool StartDocPrinter(IntPtr hPrinter, Int32 level, [In, MarshalAs(UnmanagedType.LPStruct)] DOCINFOA di);
[DllImport("winspool.Drv", EntryPoint = "EndDocPrinter", SetLastError = true, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool EndDocPrinter(IntPtr hPrinter);
[DllImport("winspool.Drv", EntryPoint = "StartPagePrinter", SetLastError = true, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool StartPagePrinter(IntPtr hPrinter);
[DllImport("winspool.Drv", EntryPoint = "EndPagePrinter", SetLastError = true, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool EndPagePrinter(IntPtr hPrinter);
[DllImport("winspool.Drv", EntryPoint = "WritePrinter", SetLastError = true, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool WritePrinter(IntPtr hPrinter, IntPtr pBytes, Int32 dwCount, out Int32 dwWritten);
public static bool SendFileToPrinter(string szPrinterName, Stream file1)
{
// Open the file.
FileStream file = new FileStream("C:\\Prova.pdf", FileMode.Open);
// Create a BinaryReader on the file.
BinaryReader br = new BinaryReader(file);
// Dim an array of bytes big enough to hold the file's contents.
Byte[] bytes = new Byte[file.Length];
bool bSuccess = false;
// Your unmanaged pointer.
IntPtr pUnmanagedBytes = new IntPtr(0);
int nLength;
nLength = Convert.ToInt32(file.Length);
// Read the contents of the file into the array.
bytes = br.ReadBytes(nLength);
// Allocate some unmanaged memory for those bytes.
pUnmanagedBytes = Marshal.AllocCoTaskMem(nLength);
// Copy the managed byte array into the unmanaged array.
Marshal.Copy(bytes, 0, pUnmanagedBytes, nLength);
// Send the unmanaged bytes to the printer.
bSuccess = SendBytesToPrinter(szPrinterName, pUnmanagedBytes, nLength);
// Free the unmanaged memory that you allocated earlier.
Marshal.FreeCoTaskMem(pUnmanagedBytes);
return bSuccess;
}
// SendBytesToPrinter()
// When the function is given a printer name and an unmanaged array
// of bytes, the function sends those bytes to the print queue.
// Returns true on success, false on failure.
public static bool SendBytesToPrinter(string szPrinterName, IntPtr pBytes, Int32 dwCount)
{
Int32 dwError = 0,
dwWritten = 0;
IntPtr hPrinter = new IntPtr(0);
DOCINFOA di = new DOCINFOA();
bool bSuccess = false; // Assume failure unless you specifically succeed.
di.pDocName = "Print Coil";
di.pDataType = "RAW";
// Open the printer.
if (OpenPrinter(szPrinterName.Normalize(), out hPrinter, IntPtr.Zero))
{
// Start a document.
if (StartDocPrinter(hPrinter, 1, di))
{
// Start a page.
if (StartPagePrinter(hPrinter))
{
// Write your bytes.
bSuccess = WritePrinter(hPrinter, pBytes, dwCount, out dwWritten);
EndPagePrinter(hPrinter);
}
EndDocPrinter(hPrinter);
}
ClosePrinter(hPrinter);
}
// If you did not succeed, GetLastError may give more information
// about why not.
if (bSuccess == false)
{
dwError = Marshal.GetLastWin32Error();
}
return bSuccess;
}
public static bool SendStringToPrinter(string szPrinterName, string szString)
{
IntPtr pBytes;
Int32 dwCount;
// How many characters are in the string?
// Fix from Nicholas Piasecki:
// dwCount = szString.Length;
dwCount = (szString.Length + 1) * Marshal.SystemMaxDBCSCharSize;
// Assume that the printer is expecting ANSI text, and then convert
// the string to ANSI text.
pBytes = Marshal.StringToCoTaskMemAnsi(szString);
// Send the converted ANSI string to the printer.
SendBytesToPrinter(szPrinterName, pBytes, dwCount);
Marshal.FreeCoTaskMem(pBytes);
return true;
}
}
最佳答案
您列出的示例代码将未经翻译的原始文件发送到打印机。此代码仅在打印机接受文件格式时才有效,并且大多数打印机无法直接解释 PDF 文件。要在大多数打印机上打印 PDF,您必须使用 Windows GDI 渲染 PDF,并让打印机驱动程序将图形转换为打印机格式。
“Print existing PDF (or other files) in C#”解决方案描述了如何使用 Ghostview 或 Adobe Reader 执行此操作。
关于c# - RawPrinterHelper 不打印并且不引发错误?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/20402821/